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What does WhatsApp use for voice call?

WhatsApp has become one of the most popular messaging apps, with over 2 billion users worldwide as of 2022. One of the key features that has driven WhatsApp’s popularity is the ability to make voice and video calls through the app, providing a convenient alternative to standard phone calls.

Voice over IP

WhatsApp relies on Voice over IP (VoIP) technology to enable voice calling capabilities. VoIP refers to the transmission of voice conversations over the internet or other IP-based networks. Instead of placing calls through traditional telephone networks, VoIP allows users to make and receive calls through an internet connection.

With WhatsApp, voice calls are made using your phone’s internet connection, whether through mobile data or Wi-Fi. The app encodes your voice into data packets that are then transmitted over the internet to the recipient’s device. This allows WhatsApp to bypass traditional telephone networks and enable free voice calling between users.

Codec

A key component that enables WhatsApp’s VoIP voice calling feature is the audio codec. A codec encodes and decodes audio signals to allow transmission over an IP network. WhatsApp utilizes the Opus audio codec to compress and transmit voice data during calls.

Opus is optimized for interactive speech and music transmission over the internet. It is designed to perform well at both low and high bitrates, making it versatile across network conditions. At higher bitrates, Opus can deliver audio quality comparable to other popular codecs like MP3 and AAC. At lower bitrates, the codec uses coding techniques to maintain good speech quality despite the constraints.

This allows WhatsApp to provide clear call quality even under shaky network connections, a common scenario in many developing markets. Opus also has lower latency compared to other codecs, which helps reduce lag during WhatsApp voice calls.

Encryption

WhatsApp also implements end-to-end encryption for voice calls between users. This means voice data is encrypted on the sender’s device and can only be decrypted by the intended recipient. The encryption protocol used is Signal Protocol, which employs state-of-the-art cryptographic techniques to secure the call.

Encryption prevents third parties, including WhatsApp itself, from accessing the contents of a call. Combined with the peer-to-peer nature of WhatsApp’s VoIP implementation, it provides users with secure voice communications.

Network connectivity

To make and receive WhatsApp calls, an internet connection is required. Here are the connectivity options supported:

Mobile data

On mobile devices, WhatsApp can utilize your phone’s mobile data connection to make voice calls. Both 3G and 4G networks allow enough bandwidth for high quality WhatsApp call connectivity.

Wi-Fi

When connected to a Wi-Fi network, your device can route WhatsApp call data over this internet connection. For optimal call quality, a high speed Wi-Fi network such as fiber or cable broadband provides robust performance.

Cellular calling

Some mobile carriers allow routing WhatsApp call data through regular cellular voice channels in addition to mobile data. This can provide an alternative connectivity option but may incur charges from your carrier.

Call quality

The quality of WhatsApp voice calls depends on factors like the network conditions and type of device. Here are some key considerations:

Bandwidth

Higher bandwidth connections like broadband Wi-Fi or 4G enable top-notch WhatsApp call quality. Under poor network conditions, call quality can deteriorate due to packet loss and lag.

Device capabilities

Smartphones with more advanced processors and optimized audio capabilities can deliver better WhatsApp calling performance. Low-end devices may suffer from choppy calls.

Background noise

Background noise from the caller’s environment can degrade call quality. Users should minimize background noise for optimal voice clarity.

Cellular signal strength

For mobile data connectivity, cellular signal strength impacts WhatsApp call quality. Weaker signals can lead to call drops or distortion.

Usage limits

WhatsApp does not impose any hard limits on voice call usage, but carriers may apply data charges or throttling in some cases:

Mobile data charges

Extensive WhatsApp calling over mobile data can lead to overage charges if you exceed your carrier’s monthly data limits. Overage fees can make frequent calling expensive.

Throttling

Mobile carriers may throttle data speeds for subscribers violating “fair usage” policies. This impacts call quality if using mobile data for WhatsApp calling.

Cellular minute allotments

If routing calls over cellular voice, your monthly minute allotment from your carrier may come into play. Going over your minutes allowance leads to overage fees.

In summary, while WhatsApp does not limit call duration, external factors like mobile carrier restrictions can impact extensive calling.

Troubleshooting

In some cases, you may encounter issues with making or receiving WhatsApp calls. Here is some troubleshooting guidance:

Check your internet connection

Ensure you have a stable internet connection, whether over Wi-Fi or mobile data. Disconnections will disrupt calls.

Restart your device

Restarting your device can resolve temporary glitches affecting WhatsApp calling.

Update WhatsApp

Ensure you are running the latest version of WhatsApp, which may resolve known call bugs.

Check your microphone settings

Make sure WhatsApp has access to your device’s microphone with appropriate permissions.

Contact your carrier

For persistent cellular calling issues, check for outages or restrictions with your mobile carrier.

Data usage

WhatsApp calls utilize data, the amount depending on call duration and other factors:

Mobile data usage

WhatsApp calls use mobile data for your cellular plan. Audio-only calls consume approx. 0.5MB per minute. Video calls use 8-12MB per minute.

Wi-Fi data usage

Over Wi-Fi, data usage is similar but WhatsApp will scale based on your connection speed. Higher bandwidth = higher data usage.

Call quality impact

In areas with poor reception, calls may use more data as the connection struggles. Try limiting call duration to manage data usage.

Flexibility

WhatsApp’s variable bitrate allows call data usage to ramp down gracefully if bandwidth becomes constrained.

In summary, WhatsApp calls can consume significant amounts of mobile data so monitoring your usage is advised.

Conclusion

WhatsApp relies on advanced Voice over IP technology to deliver seamless voice calling capabilities to billions of users worldwide. Optimized codecs like Opus and end-to-end encryption provide a top-notch combination of call quality, security and reliability. While data connectivity is required, the flexibility of operating over mobile data or Wi-Fi networks allows users to stay connected from just about anywhere. Overall, WhatsApp’s voice calling implementation sets the standard for modern IP-based communication.